Ahlgrim C, Schumacher Y O, Wrobel N, Waller C F, Pottgiesser T
Department of Exercise Medicine and Sport, University Hospital Freiburg, Hugstetterstr. 55, 79095, Freiburg, Germany,
Ann Hematol. 2014 Jul;93(7):1159-65. doi: 10.1007/s00277-014-2020-5. Epub 2014 Feb 1.
Determination of red cell volume (RCV) might contribute to establishing the diagnosis of polycythemia vera (PV). A novel simplified method to detect RCV through CO rebreathing is nowadays applied in healthy young individuals but was not tested in a clinical or PV setting. The aim of the present study is to evaluate whether this spirometric approach is applicable in older subjects and contributes to PV diagnosis in a proof-of-concept approach. At first, RCV was determined by the optimized CO-rebreathing method in healthy subjects >50 years of age (n = 81, age 66 ± 9 years). Failure rate and age distribution of subjects who failed with CO rebreathing were analyzed. Then, RCV was measured in male PV patients (n = 7) and compared to healthy male controls (n = 35). RCV values in relation to several anthropometric references (body weight, body surface area (BSA), lean body mass (LBM)) were calculated to determine the sensitivity and specificity of established RCV thresholds when using optimized CO rebreathing. In healthy subjects, test failure rate was 9.9 %, but failure was not associated with age. Sensitivity and specificity (sens/spec) to detect PV was 100 %/83 % using the criteria of the PV study group. Using criteria based on BSA, sens/spec was 14 %/100 %. An arbitrary threshold of 50 ml/kg LBM yielded sens/spec of 100 %/97 %. In conclusion, this proof-of-concept indicates that optimized CO rebreathing is applicable in older subjects and allows determining RCV for the diagnosis of PV. Normalized values for RCV measures obtained from CO rebreathing are needed to grant sufficient sensitivity and/or specificity.
红细胞体积（RCV）的测定可能有助于真性红细胞增多症（PV）的诊断。一种通过一氧化碳再呼吸检测RCV的新型简化方法目前应用于健康年轻个体，但尚未在临床或PV环境中进行测试。本研究的目的是评估这种肺量计方法是否适用于老年受试者，并以概念验证的方法有助于PV诊断。首先，采用优化的一氧化碳再呼吸方法测定年龄>50岁的健康受试者（n = 81，年龄66±9岁）的RCV。分析一氧化碳再呼吸失败的受试者的失败率和年龄分布。然后，测量男性PV患者（n = 7）的RCV，并与健康男性对照组（n = 35）进行比较。计算与几种人体测量参考值（体重、体表面积（BSA）、瘦体重（LBM））相关的RCV值，以确定使用优化的一氧化碳再呼吸时既定RCV阈值的敏感性和特异性。在健康受试者中，测试失败率为9.9%，但失败与年龄无关。使用PV研究组的标准检测PV的敏感性和特异性（sens/spec）为100%/83%。使用基于BSA的标准，sens/spec为14%/100%。任意阈值50 ml/kg LBM产生的sens/spec为100%/97%。总之，这一概念验证表明，优化的一氧化碳再呼吸适用于老年受试者，并允许确定用于PV诊断的RCV。需要从一氧化碳再呼吸获得的RCV测量的标准化值以提供足够的敏感性和/或特异性。
